In a typical space launch vehicle, small payloads may be satisfactorily launched using only a single rocket engine. Such rocket engines are well known in the art, and it is desirable to use multiples of such rocket engines to launch larger payloads to equal or higher altitudes. However, when multiple engines are used on a launch vehicle, certain performance losses occur which do not occur on a launch vehicle that utilizes only a single rocket engine.
One such performance loss occurs as a result of the fact that when multiple rocket engines having nozzles with circular exhaust areas are clustered together, the interstices between adjacent nozzles (known in the art as aft-facing base area) form flow paths for ambient air to be drawn in to the flow of the combustion products, thereby introducing turbulence into the overall flow stream rocket engines. This turbulence reduces the overall efficiency of the launch vehicle as compared to a comparable launch vehicle having a single large rocket engine. However, because a single large rocket engine for such applications would be very expensive to design and manufacture, multiple rocket engine launch vehicles are utilized despite their associated aft-facing base area performance loss.
What is needed is a nozzle for a multiple rocket engine launch vehicle that minimizes the performance loss associated with aft-facing base area.